I'd like to understand the compensation model for contractors. I've been told the client company pays the recruiting company a set amount (say, $120/hr) and whatever isn't paid to the contractor gets pocketed by the recruiting company. I've also heard that the former is a shady practice and normally the recruiting company is paid a percentage (say, 200%) of what the contractor makes. If I can understand the model of compensation, this would help me negotiate better.